AI Code Assistants for RPG Compared
A structured comparison of AI code assistants relevant to RPG and COBOL modernization on IBM i: IBM Bob, GitHub Copilot, and general-purpose chat-based assistants used ad hoc.
Developers on IBM i shops now reach for at least three different kinds of AI code assistance: IBM's own IBM Bob, general-purpose tools like GitHub Copilot, and general-purpose chat assistants such as ChatGPT or Claude used informally. They are not interchangeable. The table below compares them on the axes that actually matter for RPG and COBOL modernization work. Bob succeeded IBM's earlier watsonx Code Assistant for i preview track, reaching general availability 1.0 on March 24, 2026. The version to compare against today is Bob 2.0 with the Bob Premium Package for i, both generally available since June 24, 2026, because the Premium Package is what lets Bob work against QSYS, the IFS and Db2 for i on a live system instead of source copied to a workstation.
AI code assistants for RPG and COBOL modernization compared
| Assistant | IBM i / RPG-Specific Training | Fixed-to-Free-Format Conversion | IBM i / Db2 for i Integration | Deployment Model | Typical Use Case |
|---|---|---|---|---|---|
| IBM Bob 2.0 with the Bob Premium Package for i | Purpose-built for IBM i, using a model built into a fork of Visual Studio Code and tailored to RPG, COBOL, CL, DDS, and SQL rather than general-purpose code. The Premium Package for i adds a Developer Mode carrying IBM i language expertise and a Db2 for i Database Mode. | Supports fixed-to-free-format RPG modernization as one of roughly 40 curated skills and workflows in the Premium Package for i, alongside program explanation, refactoring, code generation, documentation, and unit tests. Succeeded IBM's earlier watsonx Code Assistant for i preview track. | About 30 IBM i tools in the Premium Package read and write source in QSYS and files in the IFS, run CL commands and SQL, launch 5250 sessions, and manage the library list. Database Mode is built specifically for Db2 for i SQL optimization with error checking. | Downloadable AI coding agent (VS Code fork) on a per-seat monthly subscription. Bob 1.0 GA March 24, 2026; Bob 2.0 and the Bob Premium Package for i GA June 24, 2026. Reported pricing from a $20 to $40 monthly add-on to $240 a month for Ultra with Premium. | Code explanation, RPG and COBOL generation from natural-language prompts, fixed-to-free conversion, automatic documentation, unit tests, and Db2 for i SQL work as part of a planned modernization project. |
| GitHub Copilot | General-purpose coding assistant trained broadly across many languages; not IBM i or RPG-specific. | Not a specific feature; may offer general code suggestions but without RPG-format-conversion awareness. | General IDE integration (VS Code, JetBrains, etc.); no IBM i or Db2 for i-specific integration. | Cloud-based subscription service integrated into supported IDEs. | General-purpose coding assistance across many languages, used by developers who also happen to touch RPG or COBOL occasionally. |
| General-purpose chat assistants (ChatGPT, Claude, used ad hoc) | General-purpose language models with broad training data that includes some RPG and COBOL, but no IBM i-specific tuning. | Not a dedicated feature; a developer can ask conversion questions manually, with variable and unverified accuracy. | None; used through a separate chat interface outside any IDE or IBM i tooling. | Cloud-based chat interface, used manually and ad hoc by individual developers. | Informal, developer-initiated question-asking or small snippet help, not a structured or repeatable part of a modernization project. |
What Else to Know
- IBM Bob is the only assistant in this comparison purpose-built and tuned specifically for RPG and the IBM i development environment. Bob 1.0 reached general availability on March 24, 2026, succeeding IBM's earlier watsonx Code Assistant for i preview. Bob 2.0 and the Bob Premium Package for i, both GA June 24, 2026, are the current versions and the ones worth comparing against.
- The Premium Package for i is the part that makes the difference in this table. Without it, Bob works against source copied to a developer workstation. With it, Bob works against QSYS, the IFS, and Db2 for i on a live system.
- GitHub Copilot and general-purpose chat assistants are broad tools that happen to have some exposure to RPG and COBOL in their training data, not IBM i-specific products.
- None of these tools should be treated as fully autonomous. Plan for developer review of any AI-suggested RPG or COBOL change before it reaches production.
- Exact feature sets, supported RPG dialects, and packaging for IBM Bob have changed more than once since the March 2026 GA release; confirm current capability and pricing directly with IBM before scoping a project.
Sources: https://bob.ibm.com/, https://www.ibm.com/products/ai-coding-agent, https://www.itjungle.com/2026/03/02/ibm-gets-bob-1-0-off-the-ground/, https://www.itjungle.com/2026/07/13/big-blue-ships-bob-2-0-and-premium-package-for-ibm-i/, https://www.ibm.com/new/announcements/introducing-the-ibm-bob-premium-package-for-i